There is a fundamental knowledge gap in how to immediately reduce cancer patients' treatment-related financial burden. Cancer patients pay more out-of-pocket for their care than those with other chronic illnesses. Half of all elderly cancer patients have high treatment-related out-of-pocket financial burden. This financial burden has well-defined harmful effects even among insured cancer patients including: worsened quality of life, more than double the risk of bankruptcy, and cancer treatment non-adherence. Hence, continued existence of this knowledge gap presents a widespread public health problem. As such, the study team has developed and demonstrated preliminary effectiveness of a theory-based, online intervention called PAPNavigator (Patient Assistance Program Navigator)?a commercially-available, interactive tool designed to help financial counselors defray patients' out-of-pocket costs. However, in busy cancer centers financial counselors do not see most patients until patients have incurred medical debt. Hence, the objective of this Fast-Track application is to develop an innovative, patient-facing mobile app (Bridge) that works with PAPNavigator to facilitate financial assistance. The central hypothesis is that Bridge will decrease financial burden (primary outcome). To test this hypothesis, in Phase I we will modify PAPNavigator to be usable directly by patients and evaluate the variant's usability and feasibility among cancer patients. In Phase II we will develop a mobile app (Bridge) to help patients plan their expenses during treatment, identify assistance programs, and coordinate with a financial counselor. We will conduct a randomized controlled trial to compare Bridge to standard-of-care financial assistance. Outcomes will be assessed with the following specific aims: Phase I specific aims: 1. Modify PAPNavigator to be usable directly by cancer patients, creating a patient-facing variant. 2. Test the usability and feasibility of the patient-facing variant of PAPNavigator in cancer patients. Phase II specific aims: 1. Develop a comprehensive mobile app (Bridge) that accurately estimates expenses during treatment and helps patients accurately identify financial assistance. 2. Determine the impact of Bridge on reducing patient out-of-pocket cost (primary outcome). 3. Determine the impact of Bridge on patient knowledge of financial resources, quality of life, and subjective financial distress (secondary outcomes). This study is significant because it focuses on financial burden, an unaddressed but widespread problem among cancer patients. The proposed research is innovative because it is the first to intervene on cancer patients' financial burden. Bridge has significant commercial potential and offers a compelling value proposition to stakeholders including patients, drug manufacturers, and patient assistance foundations.